The character John Creasy is reportedly not based on a real person. The character first appeared in the novel "Man on Fire," then in two movie adaptations of the same name.
John Creasy is a character created by late author Philip Nicholson under the pen name A.J. Quinney. The author has said that the Creasy character was based on a conglomeration of people he knew in the 1960s and 1970s rather than on one particular person. At the end of the second "Man on Fire" film, the words "John Creasy" appear accompanied by birth and death dates. This led to speculation about the character being based on an actual person.